Challenges for the Standard Cosmological Model

Posted in The Universe and Stuff with tags , , , on June 14, 2021 by telescoper

I recently came across a comprehensive review article on the arXiv and thought some of my regular readers might find it interesting as a description of the current state of play in cosmology. The paper is called Challenges for ΛCDM: An update and is written by Leandros Perivolaropoulos and Foteini Skara.

Here is the abstract:

A number of challenges of the standard ΛCDM model has been emerging during the past few years as the accuracy of cosmological observations improves. In this review we discuss in a unified manner many existing signals in cosmological and astrophysical data that appear to be in some tension (2σ or larger) with the standard ΛCDM model as defined by the Planck18 parameter values. In addition to the major well studied 5σ challenge of ΛCDM (the Hubble H0 crisis) and other well known tensions (the growth tension and the lensing amplitude AL anomaly), we discuss a wide range of other less discussed less-standard signals which appear at a lower statistical significance level than the H0 tension (also known as ‘curiosities’ in the data) which may also constitute hints towards new physics. For example such signals include cosmic dipoles (the fine structure constant α, velocity and quasar dipoles), CMB asymmetries, BAO Lyα tension, age of the Universe issues, the Lithium problem, small scale curiosities like the core-cusp and missing satellite problems, quasars Hubble diagram, oscillating short range gravity signals etc. The goal of this pedagogical review is to collectively present the current status of these signals and their level of significance, with emphasis to the Hubble crisis and refer to recent resources where more details can be found for each signal. We also briefly discuss possible theoretical approaches that can potentially explain the non-standard nature of some of these signals.

Among the useful things in it you will find this summary of the current ‘tension’ over the Hubble constant that I’ve posted about numerous times (e.g. here):

DES in the Eye

Posted in The Universe and Stuff on June 13, 2021 by telescoper

I see that the press interest in the recent Dark Energy Survey results (to which I referred in a post here) has extended to a cartoon in the latest Private Eye

On Valerian

Posted in Uncategorized on June 12, 2021 by telescoper

Pottering about in the garden this morning I remember that on my little birthday trip last week I noticed a huge amount of the above plant growing on various railway embankments between Maynooth and Dublin.

It’s red valerian (aka spur valerian, kiss-me-quick, fox’s brush, devil’s beard & Jupiter’s beard among other names). I’d like to have some on my garden, actually. It’s very attractive and is probably sufficiently hardy to survive my lack of gardening skills.

Incidentally, is is not the same species as the true valerian shown above (also known as all-heal and setwall) which is also very nice, but has lighter flowers, a very pale pink or white. You will sometimes find this interspersed with red valerian when growing wild. It grows to quite a height and is not particularly fragrant so is probably not one for the garden but is a common wild flower.

Incidentally, in Agatha Christie’s Murder on the Orient Express the victim is sedated prior to his murder using valerian, which can be taken as a tonic in the form of a dilute infusion (hence the name “all-heal”), but a powerful hypnotic in concentrated doses. It’s one of many common wild flowers that has medicinal properties but can be toxic if taken excessively.

It’s perhaps also worth mentioning that cats adore valerian in the same way they do catnip.

Boards of Examination

Posted in Biographical, Education, Maynooth with tags , , on June 11, 2021 by telescoper

We’ve at last staggered to the end of a week dominated by Examination matters. For myself that consisted of preliminary Examination Boards for Theoretical Physics and Engineering (for which we teach modules in Engineering Mathematics) followed by Final Examination Boards in both subjects with External Examiners present. Those final meetings both took place today so it’s been a particularly busy end of the week.

That’s not quite the end of the examinations business for the academic year, however, as we have the Final Final Examination Board in about ten days’ time. That is when marks from all Departments come together to determine the final results for students who are taking degrees in combinations of subjects. We have quite a number doing Joint Honours with Mathematics, for example. It does add an extra level to the process, but I think that’s a price worth paying for the flexibility we offer to students.

This final Examination Board takes place on 23rd June and students will get their marks a couple of days later on 25th June. Even that won’t be the end, because some students will be taking repeat examinations in August, but at least it signals a gap in the assessment cycle during which we can hopefully think of other things for a while.

Obviously I’m not going to comment on the marks for individual students but nobody will be surprised to hear that the Covid-19 pandemic has obviously had a big impact on some. It also had an impact on our External Examiner for Theoretical Physics who actually caught Covid-19 recently and became quite ill. Thankfully she is now feeling better and well enough to join us remotely today.

The Repeat Examination period takes place in August and will again be conducted remotely but hopefully the 1st Semester examinations next year will be under more normal circumstances. It’s not so much that I’m worried that our online examinations are somehow inappropriate, it’s just that it does take far longer to mark them than paper examinations and this year it has been extremely tight getting everything ready for the deadline by which marks must be committed to our central system (which is Monday 14th June).

Anyway, we’ve now done the job so I have an opportunity to thank all the staff in Theoretical Physics for their hard work and diligence!

Now it’s definitely wine o’clock.

The Euclid Consortium Conference Photo!

Posted in Covid-19, The Universe and Stuff on June 11, 2021 by telescoper

The Coronavirus pandemic has not only changed the nature of conferences but also changed the nature of conference photographs. Here’s the group picture of the Euclid Consortium Conference that took place via Zoom at the end of May. I’m actually in it, though I wasn’t paying attention at the time and am therefore not looking at the camera. Moreover, there are some other people who are in it several times!

Partial Eclipse Picture!

Posted in The Universe and Stuff on June 10, 2021 by telescoper

I’ve a very busy morning this morning but I’ve just got time to share this stunning picture of the partial solar eclipse happening between about 10.00am and 12.20pm across Ireland, as seen from Maynooth.

I’ll post more exciting images if and when the sky ceases to be eclipsed by clouds.

University Troubles

Posted in Biographical, Education, Maynooth on June 9, 2021 by telescoper

I noticed an article today in the Grauniad about a wave of redundancies about to hit English universities. Among those affected are the University of East London; Goldsmiths; and the University of London and the universities of Liverpool, Leeds, Leicester, Southampton Solent, Brighton. Dundee is also threatening redundancies (Higher Education is a devolved matter in the United Kingdom). There are probably many other institutions planning similar moves.

The University of Sussex, for example, has embarked on an ominous-sounding “Size and Shape” exercise that will probably lead to course and Departmental closures. “Restructuring” is the word being used. The Vice-chancellor of Sussex has refused to rule out compulsory redundancies, triggering a dispute with the Universities and Colleges Union UCU.

As regular readers will know I worked at the University of Sussex until the Summer of 2016 – was it really 5 years ago? – and when I left I was very optimistic about the future for the School of Mathematical & Physical Sciences of which I was Head. I haven’t really kept up with the details of what has been going on there but I’m not sure my optimism was well placed.

In late 2017 after I had started work here in Maynooth I wrote about my reasons for moving to Ireland. One of them was this:

My short exposure to a role in senior management, as Head of the School of Mathematical and Physical Sciences at the University of Sussex, convinced me that I didn’t want to spend the rest of my life in a system that I felt had lost all sight of what universities are and what they are for.

I haven’t changed my mind.

Anyway the timing of this attack on university staff – during a global pandemic – is rightly described in the Guardian piece as “despicable”. University staff have worked themselves into the ground by putting in countless hours of unpaid overtime to keep teaching going during the time of Coronavirus restrictions and now many of them are to be rewarded with a hefty kick in the teeth.

It’s notable too that these decisions are going to be made before the outcome of the latest Research Excellence Framework (REF 2021) are announced. This makes me doubt that the motivation for these changes has anything to do with academic considerations. It seems much more likely to me that certain university leaders see the pandemic as an excuse to force through change while staff too exhausted to resist, using the opportunity to get rid of expensive courses and/or troublesome departments.

We don’t now whether there will be widespread restructuring of the University system in Ireland but I wouldn’t bet against it. Generations of Irish governments have copied the idiotic English approach to Higher Education. The President of Ireland, Michael D. Higgins can see what’s coming. In a recent speech he highlighted the threats to academic freedom and breadth of teaching.

Full of Pfizz

Posted in Biographical, Covid-19 on June 8, 2021 by telescoper

Well, this morning I took my second trip to City West Convention Centre for my second dose of the Pfizer-BioNTech vaccine. It all went off smoothly, except the queues were very much longer than last time so it took me about 90 minutes from start to finish. Most of the extra time was spent queuing outside which wasn’t too bad because it wasn’t raining. Chatting to one of the volunteers on the way I learned that they are doing about 4,500 a day at this centre, which is getting on for 500 an hour.

When I left after my jab I noticed the outdoor queue was much longer than it had been when I joined this morning, so those just starting to wait were probably in for at least two hours before they got jabbed. Still, after everything that we’ve been missing out on for the past year and a bit, what’s a couple of hours?

Other than the increased numbers the experience was similar to my first dose: well-run, efficient and friendly. Thanks again to all concerned!

So that’s me fully vaccinated although disappointingly I don’t seem to be able to receive 5G signals and haven’t received my instructions from Bill Gates yet.

Anyway, now I’m back home about an hour later and have so far no ill-effects. We have an examination board meeting this afternoon so let’s hope I don’t flake out during it.

UPDATE: 8 hours on and I’m definitely feeling a bit tired…zzzz

UPDATE: 24 hours on, I was more-than-usually tired last night and that continues but I experienced no fevers or anything like that. Slight discomfort in the arm where the injection was given.

New Publication at the Open Journal of Astrophysics

Posted in Open Access, The Universe and Stuff with tags , , , , , on June 7, 2021 by telescoper

Time to announce another publication in the Open Journal of Astrophysics. This one was actually published on Friday actually, but I didn’t get time to post about it until just now. It is the fourth paper in Volume 4 (2021) and the 35th paper in all.

The latest publication is entitled The local vertical density distribution of ultracool dwarfs M7 to L2.5 and their luminosity function and the ultracool authors are Steve Warren (Imperial College), Saad Ahmed (Open University) and Richard Laithwaite (Imperial College).

Here is a screen grab of the overlay which includes the abstract:

You can click on the image to make it larger should you wish to do so. You can find the arXiv version of the paper here. This one is in the Astrophysics of Galaxies section but it also has overlap with Solar and Stellar Astrophysics.

Over the last few months I have noticed that it has taken a bit longer to get referee reports on papers and also for authors to complete their revisions. I think that’s probably a consequence of the pandemic and people being generally overworked. We do have a number of papers at various stages of the pipeline, so although we’re a bit behind where we were last year in terms of papers published I think may well catch up in the next month or two.

I’ll end with a reminder to prospective authors that the OJA  now has the facility to include supplementary files (e.g. code or data sets) along with the papers we publish. If any existing authors (i.e. of papers we have already published) would like us to add supplementary files retrospectively then please contact us with a request!

Lá Saoire i mí Mheitheamh

Posted in Biographical on June 7, 2021 by telescoper

It’s a Bank Holiday Monday here in Ireland which makes for a nice end-of-term break for some of us. Not all staff had exams early enough to finish in time like I did, however, and no doubt some had to spend the weekend marking exam scripts. I am fortunate to have been able to accomplish everything I intended over the weekend – nothing at all – and today I’ll be able to recover from that exertion.

The June Bank Holiday (Lá Saoire i mí Mheitheamh) in Ireland is actually the equivalent of last week’s late May Bank Holiday in the UK, in that both have their origin in the old festival of Whitsuntide (or Pentecost) which falls on the 7th Sunday after Easter. Because the date of Easter moves around in the calendar so does Whit Sunday, but it is usually in late May or early June. Here in Ireland the Bank Holiday is always on the first Monday in June whereas on the other side of the Irish Sea it is on the last Monday in May.

Although I’m only at beginners’ level in Irish, the phrase Lá Saoire i mí Mheitheamh gives me a chance to bore you about it. It’s actually quite a straightforward phrase until you reach the last word: “Lá” means “day” and “Saoire” means “leave” or “vacation” so “Lá Saoire” means “holiday”; “i” is a prepositional pronoun meaning “in” and “mí” means “month”. So far so good.

The word for June however is Meitheamh (at least when it is in the nominative singular case). As an Indo-European language, Irish is distantly related to Latin which has six grammatical cases for nouns actually seven if you count the rarely used locative case). Irish has only four cases – there’s no ablative and, curiously, no distinction between nominative and accusative. That leaves nominative, dative, genitive, and vocative. The dative – used after simple prepositions – is only rarely distinct from the nominative so basically the ones you have to learn are the genitive and the vocative.

Whereas, in Latin, cases are indicated by changes to the end of a word, in Irish they involve initial mutations. In the example of “mí Mheitheamh” meaning “month of June”, requiring the genitive form of “June”, the initial consonant “M” undergoes lenition (softening) to sound more like a “v”. In old Irish texts this would be indicated by a dot over the M but in modern orthography it is indicated by writing an “h” after the consonant. This is called a séimhiú (pronounced “shay-voo” ). Note the softened m in the middle of that word too but it’s not a mutation – it’s just part of the regular spelling of the word, as is the -mh at the end of Meitheamh. There’s also a softened “t” in the middle of Meitheamh which makes it vrtually disappear in pronunciation. Meitheamh is thus pronounced something like “Meh-hiv” whereas “Mheitheamh” is something like “Veh-hiv”.

Gheobhaidh mé mo chóta